feat(eslint-plugin): [naming-convention] add support for #private m…

…odifier on class members (#6259)

* Add `#private` as a modifier

Numbers for TypeModifiers are changed as instructed by the comment in the Modifiers enum

* Add support for `#private` modifier

* Add tests

* Add docs

Co-authored-by: Josh Goldberg <git@joshuakgoldberg.com>

packages/eslint-plugin/docs/rules/naming-convention.md

@@ -159,7 +159,7 @@ If these are provided, the identifier must start with one of the provided values
   - Accepts one or array of selectors to define an option block that applies to one or multiple selectors.
   - For example, if you provide `{ selector: ['function', 'variable'] }`, then it will apply the same option to variable and function nodes.
   - See [Allowed Selectors, Modifiers and Types](#allowed-selectors-modifiers-and-types) below for the complete list of allowed selectors.
-- `modifiers` allows you to specify which modifiers to granularly apply to, such as the accessibility (`private`/`protected`/`public`), or if the thing is `static`, etc.
+- `modifiers` allows you to specify which modifiers to granularly apply to, such as the accessibility (`#private`/`private`/`protected`/`public`), or if the thing is `static`, etc.
   - The name must match _all_ of the modifiers.
   - For example, if you provide `{ modifiers: ['private','readonly','static'] }`, then it will only match something that is `private static readonly`, and something that is just `private` will not match.
   - The following `modifiers` are allowed:
@@ -172,6 +172,7 @@ If these are provided, the identifier must start with one of the provided values
     - `requiresQuotes` - matches any name that requires quotes as it is not a valid identifier (i.e. has a space, a dash, etc in it).
     - `public` - matches any member that is either explicitly declared as `public`, or has no visibility modifier (i.e. implicitly public).
     - `abstract`,`override`,`private`,`protected`,`readonly`,`static` - matches any member explicitly declared with the given modifier.
+    - `#private` - matches any member with a private identifier (an identifier that starts with `#`)
     - `async` - matches any method, function, or function variable which is async via the `async` keyword (e.g. does not match functions that return promises without using `async` keyword)
 - `types` allows you to specify which types to match. This option supports simple, primitive types only (`array`,`boolean`,`function`,`number`,`string`).
   - The name must match _one_ of the types.
@@ -204,7 +205,7 @@ Individual Selectors match specific, well-defined sets. There is no overlap betw
   - Allowed `modifiers`: `destructured`, `unused`.
   - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
 - `classProperty` - matches any class property. Does not match properties that have direct function expression or arrow function expression values.
-  - Allowed `modifiers`: `abstract`, `override`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
+  - Allowed `modifiers`: `abstract`, `override`, `#private`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
   - Allowed `types`: `array`, `boolean`, `function`, `number`, `string`.
 - `objectLiteralProperty` - matches any object literal property. Does not match properties that have direct function expression or arrow function expression values.
   - Allowed `modifiers`: `public`, `requiresQuotes`.
@@ -216,7 +217,7 @@ Individual Selectors match specific, well-defined sets. There is no overlap betw
   - Allowed `modifiers`: `private`, `protected`, `public`, `readonly`.
   - Allowed `types`: `array`, `boolean`, `function`, `number`, `string`.
 - `classMethod` - matches any class method. Also matches properties that have direct function expression or arrow function expression values. Does not match accessors.
-  - Allowed `modifiers`: `abstract`, `async`, `override`, `private`, `protected`, `public`, `requiresQuotes`, `static`.
+  - Allowed `modifiers`: `abstract`, `async`, `override`, `#private`, `private`, `protected`, `public`, `requiresQuotes`, `static`.
   - Allowed `types`: none.
 - `objectLiteralMethod` - matches any object literal method. Also matches properties that have direct function expression or arrow function expression values. Does not match accessors.
   - Allowed `modifiers`: `async`, `public`, `requiresQuotes`.
@@ -257,16 +258,16 @@ Group Selectors are provided for convenience, and essentially bundle up sets of
   - Allowed `modifiers`: `async`, `unused`.
   - Allowed `types`: none.
 - `memberLike` - matches the same as `accessor`, `enumMember`, `method`, `parameterProperty`, `property`.
-  - Allowed `modifiers`: `abstract`, `async`, `override`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
+  - Allowed `modifiers`: `abstract`, `async`, `override`, `#private`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
   - Allowed `types`: none.
 - `typeLike` - matches the same as `class`, `enum`, `interface`, `typeAlias`, `typeParameter`.
   - Allowed `modifiers`: `abstract`, `unused`.
   - Allowed `types`: none.
 - `property` - matches the same as `classProperty`, `objectLiteralProperty`, `typeProperty`.
-  - Allowed `modifiers`: `abstract`, `async`, `override`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
+  - Allowed `modifiers`: `abstract`, `async`, `override`, `#private`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
   - Allowed `types`: `array`, `boolean`, `function`, `number`, `string`.
 - `method` - matches the same as `classMethod`, `objectLiteralMethod`, `typeMethod`.
-  - Allowed `modifiers`: `abstract`, `async`, `override`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
+  - Allowed `modifiers`: `abstract`, `async`, `override`, `#private`, `private`, `protected`, `public`, `readonly`, `requiresQuotes`, `static`.
   - Allowed `types`: none.
 
 ## FAQ

packages/eslint-plugin/src/rules/naming-convention-utils/enums.ts

@@ -91,32 +91,33 @@ enum Modifiers {
   public = 1 << 3,
   protected = 1 << 4,
   private = 1 << 5,
-  abstract = 1 << 6,
+  '#private' = 1 << 6,
+  abstract = 1 << 7,
   // destructured variable
-  destructured = 1 << 7,
+  destructured = 1 << 8,
   // variables declared in the top-level scope
-  global = 1 << 8,
+  global = 1 << 9,
   // things that are exported
-  exported = 1 << 9,
+  exported = 1 << 10,
   // things that are unused
-  unused = 1 << 10,
+  unused = 1 << 11,
   // properties that require quoting
-  requiresQuotes = 1 << 11,
+  requiresQuotes = 1 << 12,
   // class members that are overridden
-  override = 1 << 12,
+  override = 1 << 13,
   // class methods, object function properties, or functions that are async via the `async` keyword
-  async = 1 << 13,
+  async = 1 << 14,
 
   // make sure TypeModifiers starts at Modifiers + 1 or else sorting won't work
 }
 type ModifiersString = keyof typeof Modifiers;
 
 enum TypeModifiers {
-  boolean = 1 << 12,
-  string = 1 << 13,
-  number = 1 << 14,
-  function = 1 << 15,
-  array = 1 << 16,
+  boolean = 1 << 15,
+  string = 1 << 16,
+  number = 1 << 17,
+  function = 1 << 18,
+  array = 1 << 19,
 }
 type TypeModifiersString = keyof typeof TypeModifiers;
 

packages/eslint-plugin/src/rules/naming-convention-utils/schema.ts

@@ -190,6 +190,7 @@ const SCHEMA: JSONSchema.JSONSchema4 = {
       ...selectorSchema('memberLike', false, [
         'abstract',
         'private',
+        '#private',
         'protected',
         'public',
         'readonly',
@@ -201,6 +202,7 @@ const SCHEMA: JSONSchema.JSONSchema4 = {
       ...selectorSchema('classProperty', true, [
         'abstract',
         'private',
+        '#private',
         'protected',
         'public',
         'readonly',
@@ -226,6 +228,7 @@ const SCHEMA: JSONSchema.JSONSchema4 = {
       ...selectorSchema('property', true, [
         'abstract',
         'private',
+        '#private',
         'protected',
         'public',
         'readonly',
@@ -238,6 +241,7 @@ const SCHEMA: JSONSchema.JSONSchema4 = {
       ...selectorSchema('classMethod', false, [
         'abstract',
         'private',
+        '#private',
         'protected',
         'public',
         'requiresQuotes',
@@ -254,6 +258,7 @@ const SCHEMA: JSONSchema.JSONSchema4 = {
       ...selectorSchema('method', false, [
         'abstract',
         'private',
+        '#private',
         'protected',
         'public',
         'requiresQuotes',

packages/eslint-plugin/src/rules/naming-convention.ts

@@ -127,7 +127,9 @@ export default util.createRule<Options, MessageIds>({
         | TSESTree.TSParameterProperty,
     ): Set<Modifiers> {
       const modifiers = new Set<Modifiers>();
-      if (node.accessibility) {
+      if ('key' in node && node.key.type === AST_NODE_TYPES.PrivateIdentifier) {
+        modifiers.add(Modifiers['#private']);
+      } else if (node.accessibility) {
         modifiers.add(Modifiers[node.accessibility]);
       } else {
         modifiers.add(Modifiers.public);

packages/eslint-plugin/tests/rules/naming-convention/naming-convention.test.ts

@@ -867,6 +867,29 @@ ruleTester.run('naming-convention', rule, {
         },
       ],
     },
+    {
+      code: `
+        class foo {
+          private someAttribute = 1;
+          #some_attribute = 1;
+
+          private someMethod() {}
+          #some_method() {}
+        }
+      `,
+      parserOptions,
+      options: [
+        {
+          selector: 'memberLike',
+          format: ['camelCase'],
+        },
+        {
+          selector: ['memberLike'],
+          modifiers: ['#private'],
+          format: ['snake_case'],
+        },
+      ],
+    },
   ],
   invalid: [
     {
@@ -1972,5 +1995,89 @@ ruleTester.run('naming-convention', rule, {
         },
       ],
     },
+    {
+      code: `
+        class foo {
+          private firstPrivateField = 1;
+          // ❌ error
+          private first_private_field = 1;
+          // ❌ error
+          #secondPrivateField = 1;
+          #second_private_field = 1;
+        }
+      `,
+      parserOptions,
+      options: [
+        {
+          selector: 'memberLike',
+          format: ['camelCase'],
+        },
+        {
+          selector: ['memberLike'],
+          modifiers: ['#private'],
+          format: ['snake_case'],
+        },
+      ],
+      errors: [
+        {
+          messageId: 'doesNotMatchFormat',
+          data: {
+            type: 'Class Property',
+            name: 'first_private_field',
+            formats: 'camelCase',
+          },
+        },
+        {
+          messageId: 'doesNotMatchFormat',
+          data: {
+            type: 'Class Property',
+            name: 'secondPrivateField',
+            formats: 'snake_case',
+          },
+        },
+      ],
+    },
+    {
+      code: `
+        class foo {
+          private firstPrivateMethod() {}
+          // ❌ error
+          private first_private_method() {}
+          // ❌ error
+          #secondPrivateMethod() {}
+          #second_private_method() {}
+        }
+      `,
+      parserOptions,
+      options: [
+        {
+          selector: 'memberLike',
+          format: ['camelCase'],
+        },
+        {
+          selector: ['memberLike'],
+          modifiers: ['#private'],
+          format: ['snake_case'],
+        },
+      ],
+      errors: [
+        {
+          messageId: 'doesNotMatchFormat',
+          data: {
+            type: 'Class Method',
+            name: 'first_private_method',
+            formats: 'camelCase',
+          },
+        },
+        {
+          messageId: 'doesNotMatchFormat',
+          data: {
+            type: 'Class Method',
+            name: 'secondPrivateMethod',
+            formats: 'snake_case',
+          },
+        },
+      ],
+    },
   ],
 });